Since I know the people from iDalko (a plugin vendor mentioned in the question), I thought I'd email them the link to make sure they can answer the question.

They told me they received a notification around the time the question was originally posted but couldn't open the link. Probably because the question was in the SPAM quarantine.

They did not receive any notification when the question was marked NOT SPAM. I think the email notifications for questions that get marked as spam automatically should only be sent when the post is marked as NOT SPAM.